How bad is the news?

It strikes me that all an employer has to do is actually document the cost to train the individual, and use that number to prove how much more than their worth the intern received.
If the intern could make $10/hr and the cost to train them is $12/hr, then all the employer needs to do is to show that the intern has been paid 20% above their wage for the training period.

I.e. if the intern wants to get paid $10/hr for their internship, then they need to pay the $12/hr cost for that training, just like any college student has to pay tuition to receive their career training.
Obv the net upshoot is that the intern has to pay $2/hr for their training, but in a perfectly above-board, capitalism friendly way.


Where does that fail?